1. Field
One embodiment of the invention relates to an information processing apparatus having a graphics controller built in a chipset and an external graphics controller (graphics card) any one of which drives a display device.
2. Description of the Related Art
For example, of users who use personal computers, some users use applications (for, e.g., making of documents, the Internet connection, and the like) none of which apply loads to CPUs, respectively, and others use applications (such as a personal computer game and a computer graphics) which apply loads to CPUs, respectively.
For this reason, personal computer makers prepare and sell personal computers of various types including ones of a low cost type, ones of a high performance type, ones manufactured for beginners, ones manufactured for power users, and the like. In order to realize the low cost promotion, some of the personal computers which are of the low cost type or which are manufactured for beginners use a graphics memory controller hub (GMCH) having a graphics function integrated into a chipset. The GMCH borrows a part (corresponding to a storage capacity of, for example, 64 MB) of a main memory mounted to a mother board, and uses the part of the main memory thus borrowed in the form of a video memory.
Moreover, some of such personal computers can be improved in its performance without purchasing a new personal computer instead of old one by installing a high-performance graphics card which a user purchased specially or a graphics card corresponding to a use purpose of the user in an accelerated graphics port (AGP) slot or the like.
When the graphics card is added to the chipset having the graphics function integrated thereinto as described above, in order to prevent two kinds of display processing from being simultaneously executed, the graphics function of the GMCH is stopped by using a basic input output system (BIOS) of the personal computer.
A computer system including the graphics integration type chipset, for example, is disclosed in Japanese Patent Kokai No. 2001-84363. In this computer system, the graphics integration type chipset is integrated into a north-bridge. In addition, in order to improve a capability of executing display processing of the graphics integration type chipset, an external graphics processor corresponding to the graphics card is connected to the graphics integration type chipset through the AGP slot. Also, a resource is allocated to the graphics integration type chipset and the external graphics processor, and the graphics integration type chipset and the external graphics processor share the display processing for display driving, thereby making it possible to enhance the efficiency of the display processing for the graphics.
In recent years, however, the performance of the graphics card (external graphics processor) has been improved, and thus the graphics card can sufficiently execute the display processing by itself. Therefore, it cannot be said that the computer system disclosed in Japanese Patent Kokai No. 2001-84363 provides a use method which makes use of the function of the graphics integration type chipset (built-in graphics function). As a result, such a construction that the graphics integration type chipset and the graphics card share the display processing has a less necessity.